Buffer pool portion of shared memory

The buffer pool portion of shared memory contains one or more buffer pools. Each page size that is used by a dbspace has a buffer pool.

The BUFFERPOOL configuration parameter specifies the size of the buffer pool when the database server is started. If the buffer pool is extendable, the database server increases the size of the buffer pool in the buffer pool portion of shared memory.

You can determine the current size of the buffer pool portion of shared memory by running the onstat -g buf command and adding the values in the Total Mem field for each buffer pool. For example, the following output shows that the memory for one buffer pool is 32 MB:

Fg Writes     LRU Writes    Avg. LRU Time Chunk Writes  Total Mem
0             0             nan           10883         32Mb    

The maximum size of each buffer pool depends on the amount of available shared memory and the values of the BUFFERPOOL configuration parameters.